Electrocopy apparatus



March 11, 1952 E. WALKUP ET AL ELECTROCOPY APPARATUS 4 Sheets-Sheet 1Filed Dec. '7, 1948 6. ATTORNEY March 11, 1952 L. E. WALKUP ET ALELECTROCOPY APPARATUS 4 Sheets-Sheet 2 Filed Dec. '7, 1948 INVENTORSLewis E. Wolkup v Harold E Copley ix 53F BY alter AvBeckdohl we;ATTORNEY.

March 11, 1952 E. WALKUP ET AL 2,588,675

ELECTROCOPY APPARATUS Filed Dec. 7, 1948 4 Sheets-Sheet 5 INVENTORSLewis E. Walkup Harold E. Copley Walter A. Beckdohl WF M a ATTORNEYMarch 11, 1952 1.. E. WALKUP ET AL ELECTROCOPY APPARATUS 4 Sheets-Sheet4 Filed Dec. '7, 1948 ad; ATTORNEY Patented Mar. 11, 1952 UNITED STATESPATENT OFFICE ELECTROCOPY APPARATUS Lewis E. Walkup, Harold E. Copley,and Walter A. Beckdahl, Columbus, Ohio, assignors, by mesne assignments,to The Haloid Company, Rochester, N. Y., a corporation of New YorkApplication December 7, 1948, Serial No. 63,922

9 Claims. 1

This invention relates to electrocopy apparatus for making copies byelectrostatically charging a photoconductive insulating surface on aplate, exposing the charged surface while positioned over the matter tobe copied, dusting the latent electrostatic image thus produced withelectroscopic powder to form a powder image which is then transferredand fixed to a paper or other support, and it has for its purpose toafford a practical and efficient construction for carrying out thisprocedure in making contact copies of printed or typewritten matter,drawings, maps, photographs, or other records quickly and economically.

More particularly, the invention is intended to afford a compact,portable apparatus of simple and economical construction, that can bereadily operated in a small space to perform all the required charging,exposing, powder-dusting, and transfer operations required in making anelectrocopy.

Still another object of the invention is to afford a cabinet ofpractical construction that can be operated easily and quickly to chargeelectrostatically the sensitized plate carrying the photoconductiveinsulating layer when the plate is in one position in the cabinet, toexpose the plate over the matter to be copied when in another positionin relation to the cabinet, and to transfer the powder image from theplate to a paper support when in another position in the cabinet, theplate being readily positionable in the several positions necessary forcarrying out the charging, exposing, and transfer operations.

An additional object of the invention is to provide a simple andpractical form of powder-dusting mechanism which can readily be employedin conjunction with the charging, exposing, and transfer cabinet, andwhich can be operated to apply electroscopic powder to the electrostaticimage on the plate and to apply cleaning powder to the plate forremoving excess electroscopic powder therefrom after a transferoperation is completed, preparatory to using the plate for makinganother copy.

Specifically the invention has for another purpose to afford a cabinethaving lighting means therein for exposing the plate to produce anelectrostatic image, and an electrostatic charging unit movable acrossthe cabinet to charge the plate when the latter is in one position inthe cabinet above the charging unit and to transfer a powder image fromthe plate to a paper support when the plate is in another position inthe cabinet below the charging unit, ex-

posure being effected when the plate is positioned on top of the cabinetto receive light therefrom through a transparent panel on which isarranged the matter to be copied, these parts being constructed andrelated in a manner that enables a quick and efficient performance ofthe several steps.

To these and other ends, the invention consists in the construction andarrangement of parts that will appear clearly from the followingdescription when read in conjunction with the accompanying drawings, thenovel features bein pointed out in the claims following thespecification.

In the drawings:

Fig. 1 is a perspective view of a cabinet, partially broken away,showing the movable chargin unit in a position intermediate the ends ofthe cabinet as when charging the plate or transferring a powder imagefrom the plate to the paper support;

Fig. 2 is a transverse vertical sectional view through Fig. 1;

Fig. 3 is an enlarged detail vertical sectional a view takentransversely through one end of the charging unit, showing the busbar onwhich it slides;

Fig. 4 is a top plan view of the cabinet illustrated in Figs. 1 and 2,with the top wall removed and showing the electrical lighting andcontrolling means and the charging unit;

Fig. 5 is a perspective view showing the plate with its photoconductiveinsulating surface and the supporting frame therefor, with the lightshield partially removed;

Fig. 6 is a perspective view, partially broken away, showing the meansfor dusting electroscopic powder on the plate, which is illustrated inclamped position on a powder tray, the latter being removed from itssupport;

Fig. 7 is a perspective view showing a powder tray in operative positionon its support with a plate clamped therein ready for dusting;

Fig. 8 is a view similar to Fig. 7, looking toward the opposite end ofthe powder tray, and showing the clamping devices elevated in theposition assumed when a plate supporting frame is to be inserted orremoved, and

Fig. 9 is a diagrammatic view of the electrical circuit and controllingdevices.

Referring more particularly to the drawings in which like referencenumerals refer to the same parts throughout the several views and toFig. 5, the structure includes a metal conducting plate that is providedwith a photoconductive insulatductive insulating surface of the plateand protect the same from light.

In making a copy of printed or typewritten matter, a drawing, map,photograph, or other subject, it is necessary first to charge the plateI electrostatically, thereafter to expose the charged photoconductivesurface while positioned over the subject to light to form a latentelectrostatic image on the plate, subsequently dusting the electrostaticimage with electroscopic powder to form a powder image, which is thentransferred to a paper or other support and affixed in any suitablefashion, and the structure of the cabinet and parts by which theseseveral operations are effected will now be described in detail.

' Referring to Figs. 1 and 2, the cabinet includes a bottom wall 6, sidewalls 7, and a top wall 8 that is provided with a central glass ortransparent panel 9 on which the subject or matter to be copied is heldin any suitable way with the printed matter facing upwardly when thecharged plate is superposed thereover for exposure, as will be describedpresently. ll designates leaf springs mounted on the top wall 8 adjacentto the glass panel 9 for elevating the supporting frame 2 when thelatter is positioned over the glass panel to expose the charged plate inregistry therewith, the springs H raising the supporting frame 2 topermit removal of the light Shield 3 after the supporting frame andplate are in position, after which the supporting frame 2 is manuallydepressed to effect exposure, it being understood that when light isprojected from the cabinet through the glass panel 9 and through thesubject which is positioned on the glass panel facing upwardly, thesupporting frame 2 fits closely around the glass panel 9 resting uponsprings l l, and the photoconductive surface of the plate facesdownwardly and is brought into juxtarelation with the matter to becopied resting on the transparent panel 9.

Before exposing the plate, it is necessary to charge the photoconductiveinsulating surface electrostatically, and after the powder image isformed on the plate, it is necessary to transfer the same to a papersupport electrostatically, and these charging operations are performedwithin the cabinet and accomplished by electrostatic charginginstrumentalities including a charging unit slidable endwise of thecabinet and comprising a plate or shield I 2 of metal or other stiffmaterial having a series of charging wires l3 mounted above and spacedfrom its upper surface between the blocks M of any suitable insulatingmaterial and operable to spray a charge on the photoconductiveinsulating surface of the plate I and another series of spaced parallelcharging wires extending endwise of the plate I2 below the latter andspaced therefrom between the insulating blocks [6, and operable toeffect transfer of a powder image from the plate to a paper support ortransfer sheet.

The charging wires I3 and I5 are preferably spaced one-half inch fromeach other and onehalf inch from the plate I 2 which acts as a shieldbetween the two sets of charging wires 13 and I5 and in order to enablesliding the char ing unit endwise of the cabinet, one end of plate l2has fixed thereto a tongue ll that slides in a suitable guidewayprovided on the adjacent side wall I of the cabinet while the oppositeend of plate l2 carries an insulating block that is provided withmetallic bushings l8 slidable on a busbar l9 suitably fixed in thecabinet and extending endwise thereof in proximity to the adjacent sidewall I, whereby the charging unit is movable endwise on busbar [9. Thebusbar I9 is connected in suitable fashion to the electrical circuitwhile the charging wires I3 and I5 are connected in series by conductor23 and to bushing [8 by conductor 2! and thus through busbar H! to theelectrical circuit, and the charging unit is moved endwise of thecabinet manually by an operating finger 22 attached to one end of thecharging unit and extending vertically through a slot in the top walland in the guideway immediately thereunder, see Fig. 2, the operatingfinger projecting upwardly above the top Wall of the cabinet where it isaccessible for moving the charging unit endwise of the cabinet.

To charge the plate, the supporting frame 2 is inserted into the cabinetthrough the slot 23 at the front end thereof, see Fig. 1, into guideways24 formed in rails fastened to the side walls I of the cabinetimmediately above the charging unit. When the supporting frame 2 is thusinserted to charge the photoconductive insulating surface on the plate,it must be inserted so that when in position in the cabinet the slot 4is at the front end of the cabinet, permitting the light shield 3 to beinserted into the supporting frame 2 after the electrostatic charge isimposed on the plate.

When the supporting frame 2 is inserted to charge the plate I, thesupporting frame is positioned so that the photoconductive insulatingsurface I faces downwardly toward the charging unit. The supportingframe and plate close the cabinet against light during the chargingoperation at which time the lighting circuit is open. Aftertheelectrostatic charge is imposed on the plate, the light shield 3 isinserted into the supporting frame 2 before removing the latter from thecabinet.

The charged plate is then exposed by closing the lamp circuit, placingthe supporting frame 2 on top of the subject and glass panelwith thecharged plate facing downwardly, removing the light shield, and pressingthe supporting frame 2 downwardly against the springs ll, after whichthe charged and exposed plate is dusted with electroscopic powder toform a powder image in the manner that will be described presently, andwhen the powder image has been thus formed on the plate, the supportingframe 2 with the light shield 3 removedthis being unnecessary after thepowder image is formedis again inserted into the cabinet through slot 25and into guideways 25 formed in rails mounted on the side walls 1 of thecabinet under the electrostatic charging unit. The supporting frame 2 isinserted with the powder image facing upwardly toward the charging unitin order to effect transfer of the image onto a paper or other transfersheet which is positioned above and resting on the powder image when thesupporting frame is inserted into the cabinet for the transferoperation.

When the plate is inserted into the cabinet above the charging unit forcharging, the plate l2 with the charging wires l3 and 15 extendingtransversely across the plate is moved endwise .of the cabinet back andforth and an electrostatic charge is sprayed onto the photoconductiveinsulating surface by the wires I3, and during the transfer operationwhen the plate is .positioned under the charging unit with the powderimage and paper resting thereon facing upwardly, the charging unit ismoved endwise of the cabinet and an electrostatic charge sprayed fromwires I5 effects transfer of the powder image from the plate onto thesuperposed paper, after which the supporting frame .2 and paper transfersheet are removed, and the powder image afiixed to the paper as byfusing between heated plates or otherwise, by the use of volatilesolvents, or in any other suitable way.

Dusting of the charged photoconductive insulating surface withelectroscopic powder is preferably effected by the mechanism shown inFigs. 6 to 8, including a base 21 with trunnion bearings formed by ears28 having groovesor notches 29 formed therein to receive trunnions 3|carried by the side rails 32 of a tray within which is arranged theelectroscopic dusting powder 33. The powder tray is provided with meansfor clamping the supporting frame 2 thereagainst, such clampingoperation being effected by a frame including cross-rods :34 pivotallymounted in brackets 35 and carrying rails 33 having rubber or elasticpads 37 ontheir bottom edges which contact the outer surface of theplate and supporting frame 2 to clamp the latter against the tray, while38 designates any convenient form of releasable catch for holding therods 34 in their clamping position, as illustrated in Fig. 6.

To effect the powder-dusting operation and form a .powder image on theplate after the latter has been charged electrostatically and exposed,the plate with the light shield in position is positioned on thepowder-dusting tray in the manner shown in Fig. 6 with thephotoconductive insulating surface facing inwardly toward the powder.The clamping frame is then swung downwardly and the catches 38 engagedover the ends of rods 34 to hold the supporting frame 2 in clampedposition. The light shield is then removed and the dusting tray rockedon the supporting trunnion bearings 23 by lifting the free end of thetray upwardly and swinging it over until it is in reverse position orabove the sup porting frame. The powder in the tray will then fallagainst the photoconductive insulating surface I, and by moving thedusting tray upwardly and downwardly several times, the powder is causedto flow across the plate and is evenly distributed over theelectrostatic image to which it adheres. Two sets of trunnion bearingsare provided on the base 21 to permit the use .of two similar dustingtrays, one tray being filled with cleaning powder of any suitablecharacter which is used to clean the plate and remove excess or adheringelectroscopic powder after the transfer operation is completed,preparatory to using the plate for another copying operation.

In order to produce the latent electrostatic image on exposure of thecharged plate, the cabinet is provided with a series of lamps 33arranged on "the bottom wall 6 in any desirable manner. The lamps 39 are7 watt frosted bulbs arranged to give even distribution of light overthe glass panel, although a single lamp with a suitable filter or anysource of light may be used that gives uniform distribution of lightover the subject. 'The lamps are controlled 'by a suitable timer 4i andswitch button-42 that are manually operated to light the lamps .for apredetermined periodof time before exposing the plate to .the subject.43 designates a resistor that may be used in the circuit, 44 is atransformer, 45 a suitable rectifier, :and 46 is a microswitch, seeFigs. 1 and 4, located in the path of the slidable plate l2 above thecharging unit and acting automatically to open the charging circuit whenthe charging unit is in its inoperative position at one end of thecabinet, thus insuring opening the charging circuit except when thecharging unit is being moved endwise of the-cabinet to charge the plateor to effect transfer of the powder image. 41 designates a conductingcontact at the -rea.r of the cabinet beneath the transparent top panel 9and including portions arranged to be engaged by the conductive plate Iwhen the latter is inserted into the'cabinet for-charging the plate orfor transferring a powder image, in order to complete a circuit throughthe conductive plate. For charging the .plate, or transferring thepowder image, a rectified A. C. current of 6000 volts and aboutmilli-ampere can be used satisfactorily. The lamps 33 are arranged inparallel and timer 4| in series with the lamps, while the circuit to thecharging unit includes the switch 46, transformer 44, rectifier 45,charging wires [3 and I5, and the grounded shield or plate [2, all asshown.

The operation of the apparatus briefly is as follows:

Assuming the charging unit to be at the back end of the cabinet in whichposition it engages switch 46 and opens the charging circuit, the lightshield 3 is removed from supporting frame 2 and the latter is insertedthrough the slot 23 at the front end of the cabinet with thephotoconductive insulating surface I facing downwardly toward thecharging wires l3 and the slot 4 at the front end of the cabinet wheninserted into the guideways 24. Thereupon the operating finger 22 isengaged and moved endwise of the cabinet, actuating the charging unitaway from switch 46, which immediately closes the charging circuit andcauses an electrostatic charge to be sprayed from charging wires l3 ontothe photoconductive insulating surface I of the plate. This isaccomplished by moving the charging unit to the front end of the cabinetand back to its initial position, after which the light shield 3 isinserted through slot 4 into the supporting frame 2 to protect thecharged-surface from light and the supporting frame is removed from thecabinet.

Following this, the printed, typewritten, or other matter to be copiedis placed upon the transparent panel 9 at the top of the cabinet withthe printed matter facing upwardly, after which the timer 4| is set andswitch button 42 operated to close the lighting circuit and light thelamps 39 for a predetermined length of time. The supporting frame 2 ispositioned over the transparent panel 9 in registry therewith andresting upon leaf springs I I, with the photoconductive insulatingsurface I and light shield 3 facing downwardly toward the subject to becopied. When in position on the springs H, the light shield 3 is removedand the supporting frame 2 pressed downwardly against the tension ofsprings II to bring the charged photoconductive insulating surface I inclose proximity to the subject, which is resting on the glass panel 9.

It will be understood that during exposure, the electrostatic charge isdrained away from the insulating surface onto the "conductive plate inthose areas where light strikes the charged insulating surface, and inthe areas where light is prevented from striking the charged surface byreason of the black or dark areas of the matter being copied, the chargeremains on the plate and thus forms a latent electrostatic image. Thelight shield 3 is then reinserted into supporting frame Zto protect thelatent image, and the supporting frame 2 removed from the cabinet andplaced in a powder-dusting tray and clamped therein, with theelectrostatic image facing toward the interior of the tray. The lightshield 3 is then removed and the tray is rocked as already described toapply electroscopic powder over the entire surface of thephotoconductive surface uniformly and thus form a powder image.

The supportingframe 2 with the powder image thus formed on the plate isthen removed from the dusting tray after unclamping. it, and a sheet ofpaper or other transfer material laid in the supporting frame in contactwith the powder image. The supporting frame with the sheet of transferpaper resting on the powder image is then insertedthrough slot at theforward end of the cabinet into the guideways 26, until it is disposedentirely within the cabinet, with the powder image and transfer sheetfacing upwardly toward the charging wires I5. The operating finger 22vis then engaged and moved endwise of the cabinet to move the chargingunit toward the front end of the cabinet and back to its initialposition, causing an electrostatic charge to be sprayed from chargingwires l5, which acts to transfer the powder image from the plate ontothe sheet of transfer paper. a

After removal of the supporting frame 2 from the cabinet, the transferpaper with the powder image held thereon electrostaticall is subjectedto a suitable heating or fusing operation to affix the powder image, orthe latter may be permader from the plate which is then ready for another copying operation. i

If desirable, the upper charging wires I3 may be omitted from the platelz, in which case the electrostatic charging and transfer operations areboth performed by the lower charging wires l5, and during such chargingoperation, the insulating surface of the plate faces upwardly and thecharging operation is performed in a dark room, or a suitable cover ispositioned overthe trans,- parent panel 9. While the invention has beendescribed with reference to the structure shown herein, it is notlimited to the structural details set forth, and this application isintended to cover such modifications or departures as may come withinthe; purposes of the improvements or the scope of the following claims.

We claim: v 1. Electrocopy apparatus comprising a cabinet having a topwall, a transparent'panel in the top wall, lighting means within thecabinet, an elec trostatic charging unit located in and movable endwiseof the cabinet and including electrostatic charging wires extendingtransversely of the cabinet, and guideways located in the cabinet below.the charging unit to receive a plate.

charging wires extending transversely of the.

cabinet, the cabinet having a slot at its front end and communicatingguideways located below the charging unit to receive a plate.

3. Electrocopy apparatus comprising a cabinet having top wall, bottomWall and side Wallshaving a light transmitting panel in one wallthereof, lighting means within the cabinet and means to support anelectrophotographic plate against the said light transmitting panel, anelectrostatic charging unit located in and movable endwise of thecabinet and including electrostatic charging wires extendingtransversely of the cabinet, the cabinet having a slot on its front endand communicating guideways located below the charging unit to receive aplate and position it adjacent and parallel to the area of motion of thecharging unit.

4. Electrocopy apparatus comprising a lighttight cabinet having topwall, bottom wall and side walls having a transparent panel in one wallthereof to receive an electrophotographic plate for exposure, lightingmeans Within the cabinet, a support within the cabinet to receive anelectrophotographic plate for charging and an electrostatic chargingunit including at least one fine conductive strand positioned across andmovable over an area across the plate to sensitize the plate by imposinga charge on its surface. 5. Electrocopy apparatus comprising a cabinethaving top wall, bottom wall and side Walls having a transparent panelin the one wall thereof, lighting means within the cabinet and means tosupport an electrophotographic plate against the panel and facing thelighting means for exposure thereto, and an electrostatic charging unitmovable endwise of the cabinet and including electrostatic chargingwires extending transversely of the cabinet, the cabinet having a slotat its front end and communicating guideways located adjacent thecharging unit to receive an electrophotographic plate, said unit beingthereby adapted to charge an electrophotographic plate positioned on theguideways and additionally being adapted to apply a charge to a powderimage and a superposed transfer sheet positioned on anelectrophotographic plate on the guideways for transferring the powderimage from the plate to the transfer sheet.

6. Electrocopy apparatus including a cabinet:

- having top wall, bottom wall and side walls having a transparent panelin the one wall thereof, lighting means within the cabinet and means tosupport'an electrophotographic plate against the panel and facing thelighting means for exposure thereto, an electrostatic charging unitmovable endwise of the cabinet and including electrostatic chargingwires extending transversely of the cabinet, the cabinet havingguideways arranged at opposite sides extending longitudinally adjacentthe charging unitand at least one slot at the front end communicatingwith said guideways, a lighttight supporting frame, anelectrophotographic platecomprising a conductive backing and a surface,said supporting frame being slidable into the cabinet adjacent thecharging unit for charging the plate and for effecting transfer of apowder image from the plate to a transfer sheet and positionable oversaid transparent panel for exposing the plate.

7. Electrocopy charging apparatus comprising a cabinet and electrostaticcharging means located within the cabinet including a bus bar extendinglongitudinally of the cabinet adjacent to one side wall, a charging unitincluding a plate extending transversely of the cabinet and movable onsaid bus bar, and charging wires mounted on said plate extending endwisethereof transversely of the cabinet and electrically connected to saidbus bar.

8. Electrocopy charging and transferring apparatus comprising a cabinetand electrostatic charging means located within the cabinet including abus bar extending longitudinally of the cabinet adjacent to one sidewall, a charging unit including a plate extending transversely of thecabinet and movable on said bus bar, and charging wires mounted on saidplate adjacent the bus bar extending endwise of the plate andtransversely of the cabinet, the charging wires being connected to said.bus bar and the cabinet having at least one slot in one end wall andcommunicating guideways in the cabinet adjacent the charging unit toreceive a sensitized plate for charging and for transferring a powderimage from the plate to a transfer sheet.

9. Electrocopy apparatus for forming a latent electrostatic image on anelectrophotographic plate comprising a cabinet having top wall, bottomwall and side walls having a transparent 35 panel arranged in said onewall thereof, lighting means within the cabinet, a plurality ofyieldable supports arranged adjacent to said transparent panel, asupporting frame provided with an electrophotographic plate comprising aconductive backing and a photoconductive insulating coating thereon anda removable light shield, the supporting frame being positionable onsaid yieldable supports over the transparent panel to permit removal ofthe light shield and movable thereon downwardly toward said transparentpanel for bringing the sensitized plate into firm contact with thetransparent panel for exposure, and an electrostatic charging unitwithin and movable endwise of the cabinet and having charging wiresextending transversely of the cabinet, the cabinet having at least oneslot at one end and communicating guideways adjacent said charging unitto receive the electrophotographic plate for charging and fortransferring a powder image from the plate to a transfer sheet.

LEWIS E. \VALKUP. HAROLD E. COPLEY. WALTER A. BECKDAHL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 163,359 Chambers et al May 18,1875 266,564 Ward Oct. 24, 1882 271,826 Flammang Feb. 6, 1883 754,252Stevens Mar. 8, 1904 776,746 Kinsey Dec. 6, 1904 812,816 Brown Feb. 20,1906 2,011,675 Cawood Aug. 20, 1935 2,277,013 Carlson Mar. 17, 19422,357,809 Carlson Sept. 12, 1944

